Step-by-step: Digital airbrush techniques
1 I create a rough sketch based on a reference photo of a model to get the correct pose, then do a more clean line-work version on a separate layer, which includes the key characteristics of Sorayama’s robot girls. I do this pretty quickly to capture the overall feeling, but the more you spend on developing clean and accurate line-work, the better your final design will be. 2 Next, I paint a simple gradient in the background using my custom airbrush and block in the silhouette of the girl. I use a blueish grey colour to capture the plain material colour of chrome without reflections. From this point on I use this silhouette as a layer mask: this enables me to keep the outer edges of the robot/human character clean. 3 I gradually move from the mid-values in the painting towards the darks and lights. I only use Photoshop’s Soft brushes to emulate the original technique and try to replicate the classic glowing reflections from the metallic surfaces. I also start to push back my original line drawing in the same way that I would cover it with paint, as if I were using a traditional airbrush. 4 I introduce hard edges, much like how traditional airbrush artists use physical masks. I use the Lasso tools to create selections and paint inside those. I also paint in thin seam lines as small details to break up the bigger shapes. As a final touch I paint the typical glowing reflections and add some grain and noise effects, to recreate the feel of early small-sized airbrush works.